>
>Hi
>I need a 350 volts regulated power supply for a 4cx250 Linear Amp. I have
>650 volt unregulated available. The original circuit used a regulator with
>valves. I want to use solid state devices.
Sandeep:
The 4cx250B and R have: a low screen current requirement in linear
service and a tendency to generate dangerous reverse screen-current.
These two factors make the shunt zener screen regulator (powered through
a resistance connected to the anode supply) a good engineering choice.
Other benefits of a shunt regulator are: 1. Accidental loss of anode V
=s automatic loss of screen-V. 2. By chosing an appropriate series
resistance, the circuit is automatically screen current-limiting.
- A series of 5W. 20V - 30V zeners are a good choice for such a shunt
regulator because they can be mounted on a perf-board, they are
reasonably priced, and the screen V can be adjusted in 20 - 30 V steps.
However, such zeners are 5W-rated only at 25ºC case temperature - which
is quite unlikely at 5W in the real world. Thus, a "5W" zener should be
operated at no more than about 1.7 W -- except at the South Pole.
I have two sockets and a bias supply transformer that I would like to
find a home for, If you pay the postage, I will send them to you.
cheerio
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
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